NEW YORK DAY BY DAY

By Laurie Johnston and Michael Oreskes

Published: August 10, 1982

The Word on Junior's

D evotees cried last August when Junior's Restaurant in Brooklyn was destroyed by fire. Shouts of ''Save the cheesecake'' rose from the crowd anxiously watching the firefighters.

The managers of Junior's, a fixture at Flatbush and DeKalb Avenues for more than 30 years, vowed to return and they have, down to the generous stainless-steel bowls of pickles and Rumanian coleslaw on each table.

At least one customer who remembered the old days hesitated before going back to sample the famous cheesecake, fearing the hiatus might have taken its toll. Gingerly, he stepped into the orange restaurant the other evening and bought one, to be sampled at home with his family. It took only a mouthful or two. They agreed the cheesecake was its old self - light as a breeze but still rich and creamy, with no hint of a filler.

Junior's, however, has not escaped change. It now has an enclosed sidewalk cafe - with window curtains. ''It's as nice or nicer than they have in Manhattan,'' said Marvin Rosen, whose family runs the restaurant. Laurie Johnston Michael Oreskes